Set dependabot to look at composite actions versions (#6343)

.github/dependabot.yml

@@ -13,3 +13,13 @@ updates:
     schedule:
       interval: daily
     open-pull-requests-limit: 10
+  - package-ecosystem: github-actions
+    directory: "/.github/actions/build-image"
+    schedule:
+      interval: daily
+    open-pull-requests-limit: 10
+  - package-ecosystem: github-actions
+    directory: "/.github/actions/restore-python"
+    schedule:
+      interval: daily
+    open-pull-requests-limit: 10

.github/workflows/ci.yml

@@ -12,6 +12,7 @@ on:
       - "!.github/workflows/*.yml"
       - ".github/workflows/ci.yml"
       - "!.yamllint"
+      - "!.github/dependabot.yml"
   merge_group:
 
 permissions: